6.7L Cummins Forum

Squid · #1 (**permalink**) 12-25-2008, 04:37 AM

While I was talking to my mechanic about any recent flashes (I have the latest?) I asked him about the Automatic transmission maintenance requirements for our trucks.

Quote:

The 68RFE uses ATF +4 (MS-9602). Maintenance intervals are 120,000
or 60,000 miles, depending on duty-cycle (see owners manual). The
sump oil is filtered with a high-flow, advanced primary filter ( 4x4 0513470AC; and 05015267AC 4x2) different
part numbers then the 54RFE 5.9L trucks.

The fluid is filtered again when returning from transmission oil cooler, providing a double-team cleaning effort. The part numbers needed for the
external filter is Mopar 05179267

Speaking of the 54RFE here's some more info/differences.

Although the 68 uses a clutch arrangement and hydraulic control system that are similar to the 545RFE transmission, the planetary geartrain configuration and tooth counts were altered to provide the 6-speed gear ratios. The input shaft, UD shaft, OD shaft, output shaft, UD clutch, OD clutch, 2C clutch, overrunning clutch, and the entire planetary geartrain were all designed to handle the 650 ftlbs of torque from the 6.7-liter. Also, pump capacity was increased to improve fluid flow through cooler, greatly reducing overall transmission heat.

The 68 was also engineered from the ground up and “supersized” to match the power stats of the 6.7-liter Cummins and so far this is the transmission’s only application. When compared to the Allison in the GM Diesel trucks the 68 has a lower first gear ratio to improve acceleration, and a slightly wider overall gear ratio spread.

He also said that the 68 in our trucks was designed with snowplowing in mind from the beginning by Chrysler engineers who engineered the 68rfe without any bands which eliminates breakage issues from the past. The input shaft, UD shaft, OD shaft, output shaft, UD clutch, OD clutch, 2C clutch, overrunning clutch, and the entire planetary geartrain is larger to handle much higher torque numbers. Transmission fluid pump capacity is increased to improve fluid flow through cooler and reduce overall transmission heat. Also, the 68 has a significantly higher reverse gear ratio compared to its predecessor, which reduces heat generation duringplowing which I found very interesting and would also help while trying to back that huge 5th wheeler in a tight camping spot,

.

Ol'Coot · #2 (**permalink**) 12-31-2008, 10:41 AM

What is snow plowing?????

Vis-a'-vis · #3 (**permalink**) 01-04-2009, 10:56 AM

Snow plowing?? We don't need no stinking snow plowing

AKBliss · #4 (**permalink**) 03-07-2009, 12:01 PM

Here in Alaska we NEED snowplowing. Im just not into abusing my truck. I put a plow on my Polaris ranger and can keep the driveway( and all the friends that offer beer) clear. Personaly if I was going to use the truck to plow snow I would have gone with a manual tranny.

Vis-a'-vis · #5 (**permalink**) 03-07-2009, 08:05 PM

Yes, I'm sure you do...That was meant to be a joke...as Badges, we don't need no stinking Badges...I'm glad you are with us

6speeddeere · #6 (**permalink**) 12-05-2009, 03:29 PM

does the 68rfe circulate fluid while in park?

Garlic · #7 (**permalink**) 12-06-2009, 10:23 AM

I believe it does but, not at the volume it does in neutral (Just like all of the other dodge transmissions) I know that the 47RE in my 96 will take forever to engage in drive after it sets for a few weeks, place the trans in nuetral it wil only take a few seconds. It does also have 170,000 miles on it and the only work to the trans has been fluid changes. As for the 68RFE I believe it circulates in the same fashion, hence the fluid level check in Neutral instead of Park.

6speeddeere · #8 (**permalink**) 12-06-2009, 12:49 PM

thanks garlic. i thought it did but was not for sure.

Creed's Cummins · #9 (**permalink**) 12-16-2009, 07:49 AM

I was wondering, since I have seen various versions of transmissions. I believe there was a thread where it was mentioned that there was a different version for the chassis cab versus the 68RFE. On my Vehicle Information Report, it indicates that I have the transmission code DG7 - HDRFE Transmission. Is it safe to assume this is the 68RFE? Is there a way to identify the transmission type from the transmission?

Garlic · #10 (**permalink**) 12-16-2009, 08:11 AM

If memory serves me correct, the C&C's have the Aisin and the pickups (with beds) have the 68RFE. Visable difference? PTO covers on the Aisin and an external spin on filter. Squid did post a discription in this forum about how they work and the differences.
I do not recall an Aisin in a truck sold with a bed? Safe bet it is a 68RFE.

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